| タイトル | Aero-assisted orbital plane change using an elliptic drag polar |
| 著者（英） | Speyer, J. L.; Mcclendon, J. R.; Hull, D. G. |
| 著者所属（英） | Texas Univ.; Department of the Air Force |
| 発行日 | 1986-01-01 |
| 言語 | eng |
| 内容記述 | A three-impulse, aero-assisted maneuver is used to change the plane of a circular orbit. The guidance law used during the atmospheric phase is based on the repetitive use of an approximate optimal control law. The approximations include Loh's term being constant, an exponential atmosphere, and a constant-coefficient drag polar. Whereas the true optimal trajectory is flown at maximum lift-to-drag ratio, simulation results for a parabolic drag polar show the angle of attack becoming large near the end of the trajectory. Here, the approximate optimal control rule is developed for an elliptic polar which has maximum lift coefficient and higher values of the drag coefficient at high values of the lift coefficient than the parabolic polar. Simulation results show that the angle of attack still increases to high values near the end of the trajectory and that, overall, the parabolic drag polar produces better results. Finally, it is shown that Loh's term is not constant over the ascent portion of the atmospheric turn and is the probable cause of high angles of attack. However, the guidance laws developed by assuming Loh's term to be constant work well. |
| NASA分類 | ASTRODYNAMICS |
| レポートNO | 86A19779
AIAA PAPER 86-0268 |
| 権利 | Copyright |
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